#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <io.h>
#include <direct.h>
#include <dirent.h>
 
#define WIN32_LEAN_AND_MEAN
#include <windows.h> /* for GetFileAttributes */
 
#include <tchar.h>
 
#ifdef _UNICODE
#define _tdirent _wdirent
#define _TDIR _WDIR
#define _topendir _wopendir
#define _tclosedir _wclosedir
#define _treaddir _wreaddir
#define _trewinddir _wrewinddir
#define _ttelldir _wtelldir
#define _tseekdir _wseekdir
#else
#define _tdirent dirent
#define _TDIR DIR
#define _topendir opendir
#define _tclosedir closedir
#define _treaddir readdir
#define _trewinddir rewinddir
#define _ttelldir telldir
#define _tseekdir seekdir
#endif
 
#define SUFFIX _T("*")
#define SLASH _T("\\")
 
 
/*
* opendir
*
* Returns a pointer to a DIR structure appropriately filled in to begin
* searching a directory.
*/
_TDIR *
_topendir (const _TCHAR *szPath)
{
_TDIR *nd;
unsigned int rc;
_TCHAR szFullPath[MAX_PATH];
#
errno = 0;
 
if (!szPath)
{
errno = EFAULT;
return (_TDIR *) 0;
}
 
if (szPath[0] == _T('\0'))
{
errno = ENOTDIR;
return (_TDIR *) 0;
}
 
/* Attempt to determine if the given path really is a directory. */
rc = GetFileAttributes (szPath);
if (rc == (unsigned int)-1)
{
/* call GetLastError for more error info */
errno = ENOENT;
return (_TDIR *) 0;
}
if (!(rc & FILE_ATTRIBUTE_DIRECTORY))
{
/* Error, entry exists but not a directory. */
errno = ENOTDIR;
return (_TDIR *) 0;
}
 
/* Make an absolute pathname. */
_tfullpath (szFullPath, szPath, MAX_PATH);
 
/* Allocate enough space to store DIR structure and the complete
* directory path given. */
nd = (_TDIR *) malloc (sizeof (_TDIR) + (_tcslen(szFullPath) + _tcslen (SLASH) +
_tcslen(SUFFIX) + 1) * sizeof(_TCHAR));
 
if (!nd)
{
/* Error, out of memory. */
errno = ENOMEM;
return (_TDIR *) 0;
}
 
/* Create the search expression. */
_tcscpy (nd->dd_name, szFullPath);
 
/* Add on a slash if the path does not end with one. */
if (nd->dd_name[0] != _T('\0') &&
nd->dd_name[_tcslen (nd->dd_name) - 1] != _T('/') &&
nd->dd_name[_tcslen (nd->dd_name) - 1] != _T('\\'))
{
_tcscat (nd->dd_name, SLASH);
}
 
/* Add on the search pattern */
_tcscat (nd->dd_name, SUFFIX);
 
/* Initialize handle to -1 so that a premature closedir doesn't try
* to call _findclose on it. */
nd->dd_handle = -1;
 
/* Initialize the status. */
nd->dd_stat = 0;
 
/* Initialize the dirent structure. ino and reclen are invalid under
* Win32, and name simply points at the appropriate part of the
* findfirst_t structure. */
nd->dd_dir.d_ino = 0;
nd->dd_dir.d_reclen = 0;
nd->dd_dir.d_namlen = 0;
memset (nd->dd_dir.d_name, 0, FILENAME_MAX);
 
return nd;
}
 
 
/*
* readdir
*
* Return a pointer to a dirent structure filled with the information on the
* next entry in the directory.
*/
struct _tdirent *
_treaddir (_TDIR * dirp)
{
errno = 0;
 
/* Check for valid DIR struct. */
if (!dirp)
{
errno = EFAULT;
return (struct _tdirent *) 0;
}
 
if (dirp->dd_stat < 0)
{
/* We have already returned all files in the directory
* (or the structure has an invalid dd_stat). */
return (struct _tdirent *) 0;
}
else if (dirp->dd_stat == 0)
{
/* We haven't started the search yet. */
/* Start the search */
dirp->dd_handle = _tfindfirst (dirp->dd_name, &(dirp->dd_dta));
 
if (dirp->dd_handle == -1)
{
/* Whoops! Seems there are no files in that
* directory. */
dirp->dd_stat = -1;
}
else
{
dirp->dd_stat = 1;
}
}
else
{
/* Get the next search entry. */
if (_tfindnext (dirp->dd_handle, &(dirp->dd_dta)))
{
/* We are off the end or otherwise error.
_findnext sets errno to ENOENT if no more file
Undo this. */
DWORD winerr = GetLastError();
if (winerr == ERROR_NO_MORE_FILES)
errno = 0;
_findclose (dirp->dd_handle);
dirp->dd_handle = -1;
dirp->dd_stat = -1;
}
else
{
/* Update the status to indicate the correct
* number. */
dirp->dd_stat++;
}
}
 
if (dirp->dd_stat > 0)
{
/* Successfully got an entry. Everything about the file is
* already appropriately filled in except the length of the
* file name. */
dirp->dd_dir.d_namlen = _tcslen (dirp->dd_dta.name);
_tcscpy (dirp->dd_dir.d_name, dirp->dd_dta.name);
return &dirp->dd_dir;
}
 
return (struct _tdirent *) 0;
}
 
 
/*
* closedir
*
* Frees up resources allocated by opendir.
*/
int
_tclosedir (_TDIR * dirp)
{
int rc;
 
errno = 0;
rc = 0;
 
if (!dirp)
{
errno = EFAULT;
return -1;
}
 
if (dirp->dd_handle != -1)
{
rc = _findclose (dirp->dd_handle);
}
 
/* Delete the dir structure. */
free (dirp);
 
return rc;
}
 
/*
* rewinddir
*
* Return to the beginning of the directory "stream". We simply call findclose
* and then reset things like an opendir.
*/
void
_trewinddir (_TDIR * dirp)
{
errno = 0;
 
if (!dirp)
{
errno = EFAULT;
return;
}
 
if (dirp->dd_handle != -1)
{
_findclose (dirp->dd_handle);
}
 
dirp->dd_handle = -1;
dirp->dd_stat = 0;
}
 
/*
* telldir
*
* Returns the "position" in the "directory stream" which can be used with
* seekdir to go back to an old entry. We simply return the value in stat.
*/
long
_ttelldir (_TDIR * dirp)
{
errno = 0;
 
if (!dirp)
{
errno = EFAULT;
return -1;
}
return dirp->dd_stat;
}
 
/*
* seekdir
*
* Seek to an entry previously returned by telldir. We rewind the directory
* and call readdir repeatedly until either dd_stat is the position number
* or -1 (off the end). This is not perfect, in that the directory may
* have changed while we weren't looking. But that is probably the case with
* any such system.
*/
void
_tseekdir (_TDIR * dirp, long lPos)
{
errno = 0;
 
if (!dirp)
{
errno = EFAULT;
return;
}
 
if (lPos < -1)
{
/* Seeking to an invalid position. */
errno = EINVAL;
return;
}
else if (lPos == -1)
{
/* Seek past end. */
if (dirp->dd_handle != -1)
{
_findclose (dirp->dd_handle);
}
dirp->dd_handle = -1;
dirp->dd_stat = -1;
}
else
{
/* Rewind and read forward to the appropriate index. */
_trewinddir (dirp);
 
while ((dirp->dd_stat < lPos) && _treaddir (dirp))
;
}
}
